Mitsubishi Electric FR-F820-00046, Instruction Manual

Page: 836 / 940

Causes and corrective actions Protective functions
6 - 24
Operation panel
indication
E.LF FR-LU08 Output phase loss
Name Output phase loss
Description
The inverter trips if one of the three phases (U, V, W) on the inverter's output side (load side) is
lost.
Check point
Check the wiring. (Check that the motor is normally operating.)
Check that the capacity of the motor used is not smaller than that of the inverter.
Check if a start command is given to the inverter while the motor is coasting.
(PM motor control)
Corrective action
Wire the cables properly.
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function (page 5-423).
(PM motor control)
Operation panel
indication
E.OHT FR-LU08 Ext TH relay oper
Name External thermal relay operation
Description
The inverter trips if the external thermal relay provided for motor overheat protection or the
internally mounted thermal relay in the motor, etc. switches ON (contacts open).
This function is available when "7" (OH signal) is set in any of Pr. 178 to Pr. 189 (input terminal
function selection). This protective function is not available in the initial status. (OH signal is not
assigned.)
Check point
Check for motor overheating.
Check that the value "7" (OH signal) is set correctly to any of Pr. 178 to Pr. 189 (input terminal
function selection).
Corrective action
Reduce the load and operation duty.
Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.
Operation panel
indication
E.PTC FR-LU08 PTC thermistor oper
Name PTC thermistor operation
Description
The inverter trips if resistance of the PTC thermistor connected between the terminal 2 and
terminal 10 is equal to or higher than the Pr. 561 "PTC thermistor protection level" setting for a
continuous time equal to or longer than the setting value in Pr. 1016 "PTC thermistor protection
detection time". When the initial value (Pr. 561 = "9999") is set, this protective function is not
available.
Check point
Check the connection with the PTC thermistor.
Check the Pr. 561, Pr. 1016 setting.
Check the motor for operation under overload.
Corrective action Reduce the load.